1. ## algebra rewriting

If x=1/4-y, evaluate

1/x + 4x + y -yx -1

2. Originally Posted by math123456
If x=1/4-y, evaluate

1/x + 4x + y -yx -1

i suppose you mean this:

If $x = \frac 1{4 - y}$, evaluate $\frac 1x + 4x + y - yx - 1$

note that, since $x = \frac 1{4 - y}$, we have $\frac 1x = 4 - y$

so our expression is:

$4 - y + \frac 4{4 - y} + y - \frac y{4 - y} - 1$

now simplify